1. Field of Invention
This invention pertains to large scale, industrial water purification systems. More particularly, the invention pertains to a water conversion system for converting contaminated water, such as produced water and frack flow back water from hydrocarbon field drilling and hydrocarbon production, and from other contamination sources, to fresh, non-contaminated or potable water.
2. Description of the Related Art
Hydrocarbon wells typically produce water in addition to oil and gas. This water is called “produced water.” Produced water often arises from the fact that oil and gas reservoirs have a natural water layer (formation water) that lies under the hydrocarbons. Further, to achieve maximum oil recovery, additional water is often injected into the reservoirs to help force the oil to the surface or break up the formation to produce more oil and/or gas, which is referred to as “fracking.” A significant percentage of the injected water, referred to as “frack flow back water” or “simple flow back water” herein, flows back out of the well, particularly in the first few weeks of production from the well after fracking. Modern industrial operations, such as soy food processing and refining, cleaning of sea water in ships and oil platforms, and many other industrial operations produce contaminated water sources.
In the prior art, produced water, flow back water, mining water, and other contaminated waters were disposed of by injecting the water into the earth or evaporating it in lined pits or ponds, both of which are costly and are not environmentally sound, as they essentially are ways to postpone dealing with the contaminants. Thus, both of these have become an increasingly unacceptable disposal method from both environmental and social perspectives. Produced water and flow back water are considered an industrial waste and laws have begun to be enacted requiring producers to recycle this water. Producers also understand that there is both short-term and long-term liability in disposing of contaminated water in disposal wells and evaporation ponds, and recycling would mitigate that liability. Moreover, suitable places for injecting or pits for storing produced water often are not available near the production site. Thus, produced water and flow back water are often shipped tens to hundreds of miles to disposal sites in trucks. In regions where produced water and/or flow back water are being trucked, large numbers of trucks travel over back country roads that are negatively affected by the heavy traffic. Further, the large numbers of trucks are sources of air pollution. In addition, shipping of produced water and flow back water to remote disposal sites is costly, and the sites must be maintained indefinitely. As a hydrocarbon field becomes depleted, the produced water content of the oil or gas increases. This often leads to more fracking and more flow back water. This adds to the cost of recovering oil and gas, just when the return on the wells is dwindling. This can lead to the abandonment of wells that still contain significant amounts of oil or gas.
A further problem with recycling or disposing of the contaminants in produced water is that each source of produced water, flow back water, and water from other industrial sources, such as soy bean oil production and water from ships, is different, which requires that the treatment to decontaminate and recycle it must be different for each well. This makes it prohibitively expensive to recycle produced water and flow back water, so injection and evaporation in pits still remains the primary way of disposing of produced water. For the above reasons, it would be highly desirable if a way to recycle and decontaminate produced water, frack flow back water, and other industrial waters were available that was sufficiently flexible to be able to handle produced water, frack flow back water and other water from a variety of different sources.